*{
    padding:0;
    margin:0;
}
body{
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    background-color: #222;
}
a{
    position: relative;
    display: inline-block;
    font-size: 18px;
    padding: 12px 36px;
    margin: 10px 0;
    color: #fff;
    text-decoration: none;
    /* 转为大写 */
    text-transform: uppercase;
    letter-spacing: 2px;
    border-radius: 40px;
    background:linear-gradient(90deg,#0162c8,#55e7fc) ;
    overflow: hidden;
}
a:nth-of-type(2){
    background:linear-gradient(90deg,#755bea,#ff72c0) ;
}

span{
    position: absolute;
    background-color: #fff;
    transform: translate(-50%,-50%);
    pointer-events: none;
    border-radius: 50%;
    animation:animate 1s linear infinite;
}

@keyframes animate{
    0%{
        width:0;
        height: 0;
        opacity: 0.5;
    }
    100%{
        width:500px;
        height: 500px;
        opacity: 0;
    }
}